Masonry is one of the most common construction materials globally. Tens of billions of ordinary concrete blocks are used on construction sites every year, to create durable, cost-effective buildings.
However, this durability comes at a high cost to the environment. Most masonry products, including conventional gray concrete blocks, are made by mixing sand and gravel together, with Portland cement. The worldwide use of Portland cement contributes significantly to greenhouse gas emissions, currently accounting for about 6 to 7 percent of all greenhouse gas emissions globally, due largely to the amount of energy required to produce it. In addition, the energy required to blast and crush virgin rock into gravel and sand, which are then used to make the blocks, further contributes to the carbon footprint that results from the extensive use of ordinary masonry materials. Therefore, the widespread use of concrete products for buildings is currently accelerating environmental decline.
Conventional concrete blocks are rarely manufactured close to where they are used. This means that such concrete blocks are typically transported, often at great distances, at a further economic and environmental cost.